In a medium bowl prepare the marination by combining the chicken, yogurt, lemon juice, garlic, ginger, chili powder, ground cumin, garam masala, and salt. Allow the chicken to marinate for at least 30 minutes (preferably overnight).
Heat a large skillet on medium heat and add oil. Once the oil is heated add the chicken pieces and cook for 5-6 minutes until lightly browned. Transfer the cooked chicken pieces to a plate and set them aside.
To the same skillet add 1 tablespoon of oil. Add the onion and garlic, saute for 3-5 minutes until the onions turn translucent.
Add in the spices; paprika, coriander, garam masala, salt, and turmeric powder. Saute for a minute.
Stir in the tomato sauce and cook for a couple of minutes. Once the sauce is thickened add the coconut milk and cook for 5 minutes.
Once the tikka masala starts bubbling add the chicken back to the pot and allow the masala to simmer for 10 minutes on a low flame.
Once the chicken is cooked through add in the chopped cilantro and turn off the heat.
Serve the creamy chicken tikka masala with a bowl of rice to enjoy!